Salmon Island, a treeless sliver of land in Lake Ontario, is a precarious place to breed if you’re a herring gull. Yet every spring they return.

Ring-billed gulls, the ones that we associate with scavenging for food in dumps, take flight on East Brother Island with the arrival of Chip Weseloh. The ornithologist studies birds on Lake Ontario for Environment Canada.

By:Sandro ContentaFeature Writer, Published on Fri Jul 15 2011

Salmon Island is a treeless sliver of land in Lake Ontario, its low-lying existence threatened by every wave.

It’s a precarious place to breed if you’re a herring gull. Swells can wash away nests and eggs, reducing a season’s courting, mating and incubation to wasted effort. Yet every spring they return, as does Chip Weseloh.

Weseloh, an ornithologist with Environment Canada’s wildlife service, has been monitoring the health of water birds that nest in colonies on the Great Lakes for more than 30 years. He’s watched herring gulls and other species bounce back from the ravages of egg-thinning PCBs and DDT since the late 1970s, when the contaminants were banned or phased out.

“There’s lots of good news stories when it comes to pollution on the Great Lakes because things are much, much better than they used to be,” says Weseloh, 65. “But there are new contaminants coming on the scene that we don’t know the effects of and that haven’t been studied as well. So you always have to stay vigilant.”

So Weseloh is back on Salmon Island, some two kilometres from Kingston’s shores, where he has planted numbered stakes next to 40 herring gull nests. It’s one of several islands in the Great Lakes where Weseloh and his colleagues monitor reproduction, along with 15 others where they also keep track of contaminants.

It’s a sunny morning in mid-May. At the sight of human intruders, the gulls take flight, filling the air with irritated squawks. A couple of disturbed nests along the island’s sandy edges are empty, their eggs probably washed away. The rest are each filled with three olive-coloured eggs with spots.

“They always lay three eggs,” Weseloh says. “If you take one away they’ll replace it. And if you take it away again, they’ll replace it again. They’ve done studies to see just how many eggs they’ll put back — you’ll get over a dozen if you keep taking the eggs away.”

The eggs are warm, almost hot, from incubation. One nest has two chicks that have already hatched. They’re “precocial” birds, the type born with down, open eyes and the strength to move. At a day and a half old, they’re beige and grey balls of spotted fluff. One pants as if overheating while its sibling climbs over it.

Inside the nest’s third egg, a chick is “pipping.” The term sounds too cheerful for the enormous effort the scrunched-up chick must be exerting. It has broken through just enough to stick out its beak, the tip of which has a tiny, and temporary, “egg tooth”— an evolutionary tool to jackhammer out the shell.

“He’s already been working at this for about 18 hours,” Weseloh says. “He’ll probably be out of it by the end of the day.”

Seventy to 80 per cent of the herring eggs in a colony usually hatch. If not eaten by predatory adults, the chicks fly within seven weeks and migrate when young, but stay year-round on the lakes once fully grown. They begin to breed at three or four years of age, often doing so on the site where they were born.

“If they have a place where their nest has been successful — let’s say at the very end of the island — both individuals may come back there to nest and they all of a sudden say, ‘Hey, I nested with you last year here,’ ” Weseloh says. “So, I don’t think gulls mate for life but I think they have a fidelity to a site and that leads to having the same mate again.”

He’s seen some birds return to nest on the same island six years in a row. “You become attached to those birds,” he says.

A gull then dives like a bomber from the sky and streaks inches from a Star reporter’s head.

“Herring gulls will actually hit you on the head,” Weseloh says. “I’ve had blood drawn on my skull many times.” And that explains the toque he’s wearing.

There are other hazards in his job. His outboard motor dies and he’s left stranded, or the fog rolls in and he’s reduced to finding islands by sniffing for guano.

He is based at the wildlife service’s Downsview office and lives in Toronto, where he raised four biological children and several foster children. Weseloh has a summer cottage on Garden Island near Kingston.

Satisfaction also comes from having watched populations of colonial water birds recover. There are nine species that nest in colonies on the Great Lakes — herring gulls, ring-billed gulls, great black-backed gulls, double-crested cormorants, common terns, Caspian terns, black-crowned night-herons, great blue herons and great egrets. (Waterfowl — ducks, geese and swans — also nest on the lakes or their rivers and marshes. But not in colonies.)

Weseloh’s work helps Canadian and American authorities produce a census of the Great Lakes’ colonial water birds each decade. The effort was triggered by the sad state of herring gulls in the 1970s, when only 300 nests remained. On one island, just 10 of 300 eggs hatched.

A crackdown on contaminants helped turn numbers around to almost 1,000 herring gull nests by the first decade of the 2000s. Weseloh has noticed their numbers dip in recent years, so he’s keeping close watch.

The sharp decline in common terns — a 50-per-cent drop in nests since the 1970s — is causing the greatest concern. Forty years ago, for example, 16,000 pairs of common terns were nesting in Presqu’ile Provincial Park. Today, there are two or three.

Part of the problem is that terns are being bullied out of nesting grounds by ring-billed gulls. Ornithologists are now covering those grounds around Toronto and Hamilton with plastic sheets to keep the ring-billed away, and removing them later when the terns arrive on their migration.

Contaminants in the lakes are also under suspicion, particularly polybrominated diphenyl ethers, or PBDEs — chemicals used as flame retardants and added to plastics, electronics and upholstered furniture. The Canadian government has a plan to ban all PBDEs by 2013.

“PBDEs are one of the (chemicals) they’re worried about and are tracking now,” Weseloh says, referring to Environment Canada scientists. “They don’t know the effects of those compounds as well as they know the effects of some of the others.”

What is known is that PBDEs are having an impact on the metabolism of herring gulls, Weseloh says.

“They don’t seem to be affecting the birds on a population level but on individuals you’re having some physiological damage and problems. Whether that affects the number of chicks that will hatch at the end of the season remains to be seen.”

The whole area of substances in the lake is a bit of a guessing game. Environment Canada has identified more than 360 chemical compounds in the Great Lakes, many of them dangerous to humans and the aquatic ecosystem. But Weseloh says companies are not obliged to inform Environment Canada about the chemicals they’re dumping.

“Companies, as far as I know, very seldom tell you what is going into the water.

“Our chemists can run the (water) samples through the machines and they’ll get spikes or blips that they don’t know of, and then they’ll start investigating those. So we can kind of get at it by the back door. It would be nice if we just had a big list of what is being put in by everybody.”

Botulism has wiped out the 50 pairs of great black-backed gulls from the eastern part of Lake Ontario. But they’re a highly predatory bird, so some bird lovers are happy to have seen the last of them. They’re also a hearty species, and Weseloh believes they’ll eventually make a comeback.

Great egrets are increasing and ring-billed gulls have prospered. But no species has done as well as the double-crested cormorant.

“Cormorant populations have increased astronomically,” Weseloh says.

In the 1950s there were about 1,000 pairs of cormorants on the Great Lakes. In the 1970s, pollution and DDT crashed their numbers to 100 pairs. By the 2000s, Canadian and U.S. surveys counted more than 100,000 nests and pairs of double crested cormorants.

The downside of the cormorants’ success story is obvious on West Brother Island, also near Kingston, the next stop on Weseloh’s reproduction tour. The island’s trees stand bare and ghostly white, like sculptures of the apocalypse, killed by the poop of cormorants nesting on their branches.

When the dead trees fall, the birds build their nests on the ground. Why they don’t nest on the ground to begin with, and thus spare the trees, is a mystery. Also a mystery is why cormorant poop is deadlier to trees than the excrement of other birds, Weseloh says. Whatever the reason, Kingston’s residents aren’t happy about the slow death of their nearby islands.

On the U.S. side of the Great Lakes, officials are trying to reduce cormorant populations with full-scale campaigns that involve either oiling eggs or shooting the birds. On the Canadian side, Weseloh says, those methods are being used near Point Pelee National Park and Presqu’ile.

There are 150 pairs of double-crested cormorants nesting on West Brother Island. They fly off as Weseloh’s boat docks and wait patiently on the lake as he inspects their nests. Also on the small island are the nests of 150 pairs of herring gulls and 50 pairs of ring-billed gulls.

Weseloh picks up a ring-billed gull that has died recently. It has “brooding patches” on its belly — circles where the feathers have fallen off so the bird can better incubate its eggs. A ring-billed then swoops down from above and unloads a well-aimed waste bomb that smacks a Star reporter on the shoulder.

“You just got shit on,” Weseloh says with a smile, probably happy that, for once, it has happened to someone else. “It’s a status symbol. If you’re a real field biologist, you get shit on.”

Back in his boat, the wind and sun in his face, Weseloh heads to shore.

“Another hard day at the office, eh,” he shouts over the motor’s roar. “It’s crappy work, but someone’s got to do it.” Then he flashes a big smile.

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